Sitcom mischief with cartoonist Hank Ketcham's comic-strip terror who really didn't mean to do all those things that drove Mr. Wilson crazy. Joseph Kearns, who played Mr. Wilson, died midway through the 1961-62 season. He was replaced by Gale Gordon as Mr. Wilson's brother, John, who moved into his brother's house (with his own wife, played by Sara Seeger), giving Dennis another Mr. Wilson to torment.